Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-di03.r1000.mx.aol.com (Internet Inbound) with ESMTP id AE0713800008E; Sun, 13 Jan 2013 12:03:10 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1TuQwx-0001TA-M0 for rs_out_1@blacksheep.org; Sun, 13 Jan 2013 17:02:23 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1TuQwx-0001T1-5o for rsgb_lf_group@blacksheep.org; Sun, 13 Jan 2013 17:02:23 +0000 Received: from out1.ip05ir2.opaltelecom.net ([62.24.128.241]) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1TuQwv-0001sH-Cv for rsgb_lf_group@blacksheep.org; Sun, 13 Jan 2013 17:02:22 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AgEFAC/o8lBcHYgt/2dsb2JhbABEvgMXc4IZBQEBBQgBAQNJAiwBAQMFAgEDEQQBAQolFAEEGgYWCAYTCgECAgEBCogCsz6NB4QnA4gshVGYV4J1 X-IronPort-AV: E=Sophos;i="4.84,464,1355097600"; d="scan'208,217";a="405363536" Received: from host-92-29-136-45.as13285.net (HELO xphd97xgq27nyf) ([92.29.136.45]) by out1.ip05ir2.opaltelecom.net with SMTP; 13 Jan 2013 17:01:56 +0000 Message-ID: <007c01cdf1af$b0eb8bd0$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <006601cdf1a8$5bcd66c0$0401a8c0@xphd97xgq27nyf> <50F2E105.20505@iup.uni-heidelberg.de> Date: Sun, 13 Jan 2013 17:01:54 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Spam-Score: 3.3 (+++) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Stefan Your proposed solution is a Compromise so there will be losses or problems, If a switch is necessary use a large motor driven ceramic switch. I have seen some very large ceramic switches about that will handle your power. or a Decca type relay with a very large GAP Problems can be over come, there is hardware about for the job, but keep it simple is the best solution !! [...] Content analysis details: (3.3 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_MESSAGE BODY: HTML included in message 3.3 AXB_XMAILER_MIMEOLE_OL_024C2 AXB_XMAILER_MIMEOLE_OL_024C2 X-Scan-Signature: d5ac66e7920295f519efeb68ecc59e6f Subject: Re: LF: Variometer es Loading coils Content-Type: multipart/alternative; boundary="----=_NextPart_000_0079_01CDF1AF.B0B70E50" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,HTML_MESSAGE autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-global-disposition: G x-aol-sid: 3039ac1da60750f2e8ce0e72 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_0079_01CDF1AF.B0B70E50 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Stefan Your proposed solution is a Compromise so there will be losses or = problems, If a switch is necessary use a large motor driven ceramic = switch. I have seen some very large ceramic switches about that will = handle your power. or a Decca type relay with a very large GAP Problems can be over come, there is hardware about for the job, but keep = it simple is the best solution !! 73 gl de mal/g3kev ----- Original Message -----=20 From: Stefan Sch=E4fer=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Sunday, January 13, 2013 4:29 PM Subject: Re: LF: Variometer es Loading coils Am 13.01.2013 17:09, schrieb mal hamilton:=20 If I needed two loading coils for one antenna to cover LF es MF I = think I would use one Loading coil and short out turns not required for = MF and one Variometer would do both. But then the switch has to withstand the HV when TXing on MF. Also the = switch is not at ground potential. And if a matching transformer is used = near the coil (to transform from or to 50 Ohm), it has to be dimensioned = for both LF and MF. However if the LF losses strongly differ from the MF = losses, the transformation is not ideal. Also the range that is covered = from the small variometer coil may be much to large for MF, so it is = tricky to resonate on MF :-/ I do not have a loading coil on MF because the antenna is a full = size 1/4 wave inv L for MF and a separate antenna system for LF with = around 400 uH loading/matching coil, no variometer, turns tapped up/down = for a 50 ohm match. This is one method to go. But a (isolating) transformer near the coil = has some advantages like decoupling the earth (clean LF earth from noisy = mains earth) and a high inductance of the transformer then the 50 Ohm = side is not connected (that detunes the antenna and may help to reduce = local QRM). 73, Stefan de g3kev ------=_NextPart_000_0079_01CDF1AF.B0B70E50 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Stefan
Your proposed solution is a Compromise so there = will be=20 losses or problems,  If a switch is necessary use a large motor = driven=20 ceramic switch. I have seen some very large ceramic switches about that = will=20 handle your power. or a Decca type relay with a very large = GAP
Problems can be over come, there is hardware = about for the=20 job, but keep it simple is the best solution !!
 
73 gl de mal/g3kev
 
----- Original Message -----
From:=20 Stefan = Sch=E4fer
Sent: Sunday, January 13, 2013 = 4:29=20 PM
Subject: Re: LF: Variometer es = Loading=20 coils


Am 13.01.2013 17:09, schrieb mal hamilton:=20
If I needed two loading coils for one = antenna to cover=20 LF es MF I think I would use one Loading coil and short out turns = not=20 required for MF and one Variometer would do = both.
But=20 then the switch has to withstand the HV when TXing on MF. Also the = switch is=20 not at ground potential. And if a matching transformer is used near = the coil=20 (to transform from or to 50 Ohm), it has to be dimensioned for both LF = and MF.=20 However if the LF losses strongly differ from the MF losses, the=20 transformation is not ideal. Also the range that is covered from the = small=20 variometer coil may be much to large for MF, so it is tricky to = resonate on MF=20 :-/

I do not have a loading coil on = MF because the=20 antenna is a full size 1/4 wave inv L for MF and a separate antenna = system=20 for LF with around 400 uH loading/matching coil, no variometer, = turns tapped=20 up/down for a 50 ohm match.
This is one = method to go.=20 But a (isolating) transformer near the coil has some advantages like=20 decoupling the earth (clean LF earth from noisy mains earth) and a = high=20 inductance of the transformer then the 50 Ohm side is not connected = (that=20 detunes the antenna and may help to reduce local QRM).

73,=20 Stefan

 
de g3kev
 
 
------=_NextPart_000_0079_01CDF1AF.B0B70E50--